Beliefs should be open to revision, have been scrutinized before believing, needing valid and reliable reason and evidence. But then you have most religious believers who accept beliefs with no proof at all, just empty faith. Stubbornly they adhere to religious beliefs, which are either completely insufficiently proven beliefs at best and outright myths and lies otherwise.
Such religious believers’ beliefs are not at all open to revision; either, they are shallow thinkers that are quite flexible, and just how the beliefs were acquired so to the current religious go unscrutinized, just as they did before believing. And faith, the mental infection of clear thinking, continues over requiring a scrutinizing of all things before believing, needing valid and reliable reason and evidence.